During digital image processing, detail information of the image needs to be fully displayed, and thus an edge enhancement is required. The edge of the image refers to an area of the image which has an obvious brightness variation.
Nowadays, there are a lot of methods for enhancing the edge of the image, for example, Sobel algorithm, Robert algorithm, Robinson algorithm, Laplace algorithm, etc., in which Sobel algorithm is most commonly used.
Sobel algorithm has advantages of simplicity and fast processing speed. However, the resolution of the processed image using the Sobel algorithm is low.